Hollow
by Kni9ht
Summary: In a world where they had never met each other, what would they have become?
1. Hollow

**...**

_**HOLLOW**_

**...**

Rias Gremory isn't someone who would easily feel lonely.

Well, of course. Being born into an affectionate house, living a full-filling school life, and forming bonds with the servants that were almost like a second family to her, she was having what you could have called the epitome of a perfect lifestyle.

Yet, she still felt some parts of her missing somewhere.

Did it have anything to do with how she constantly opened the curtain of the Occult Club's room and gazed down at an empty bench; how she always imagined another silhouette with brown hair whenever she wanted to hug something for comfort; or how she kept twirling the piece of «Pawn» in her hand mindlessly, unaware of the time passing by?

Honestly, Rias didn't know.

In addition, she always felt that everyone was looking at her with either eyes of admiration or gazes of envy, even her closest acquaintances. Nobody had ever understood her true self. Perhaps, what she had been waiting for was something, someone who was capable of seeing her beyond what she appeared to be.

There was times when she got tired of waiting and went to look for that thing herself.

But no matter how hard she tried to search, it simply wouldn't come to her despite her seemingly hopeless efforts. It kept evading her times and times again, until she, inevitably, hit her limit and gave up on it. Then everything went back to the way it used to be.

And just like a breeze, years of her youth had passed by quietly.

Even though Rias was living happily as she could, somehow, a hole appeared inside her heart and kept getting bigger, until it became hollow.

**...**

It was unusual of Rias to lie helplessly with nothing but an empty expression on her couch in the Occult Research clubroom, and yet she couldn't do anything about it. Perhaps to her, it might as well be the last time she got to feel the sense of solidarity in a place that she had become attached to.

The reason for her current wretched state was her engagement.

As a pure-blooded Devil descendant of noble class, she was bound to have some duty to perform, one of which is to marry the person that her parents had chosen for her.

The most aggravating thing was that she hated her soon-to-be fiancé, namely Riser Phenex, with every vein of her heart.

Imagine someone who dressed like a rich delinquent with no sense of delicacy, consideration or whatsoever. Not only that, he also flirted with every pretty girl he could see and made out with one of his peerage members randomly (which totally consisted of females that he had gathered according to his fetishes).

The worst thing is that he obviously desired her body from the very first moment they met. She could easily point it out with him constantly using vulgar words in front of her and his ogling gaze of lust.

Rias absolutely despised him, and she sometimes wished that guy had never been born, much less than meeting him. Of course, being a resolute woman, Rias didn't stay still and let things just go on their own like that. She challenged Riser into a Rating Game match, which if he lost, he would have to call off the engagement.

Strong as she was, determined as she was, Rias couldn't, however, win the match. It wasn't that she was weak, nor her servants were incapable of protecting their master. Their opponents were just too powerful and too numerous for them to fight against.

With her fate being set, Rias had given up the idea of finding a true love of her own. All the fairy tales she had read, all the romantic novels she had mused on were lost and turned into unreachable fantasies that she could never have.

Which is the reason why she was so vulnerable right now, with her heart being broken and shattered. And it was also in these moments of weakness that she bitterly realized one fact.

The only thing she truly had left to herself was the hole inside her heart, and those very same hollow feelings were still in there, if not getting stronger.

**...**

It was a life-threatening situation.

Rias had lived most of her life in peace, granted that it mainly had to do with the temporary truce between the Three Great Factions, thus she wasn't accustomed to this kind of peril.

The Old Maou Faction had decided on an all-out coup d'état in the Underworld. With that call, the remnants of the Old Devils rose up everywhere and began a massive genocide on the Young Devils who had, according to the slaughterers, 'strayed from the path of true Devils'. They were even able to gather many dangerous Sacred Gears users and Holy/Demonic Swords wielders, as well as a user of one top-rated Longinus, «Annihilation Maker», which created many gigantic monsters invading the Underworld. In addition to that, some heretic Fallen Angels used this opportunity to wreak havoc, and Devils-incarnated who were resentful towards their masters' treatment also joined in the fray. As such, the entire dimension was being thrown into a state of utter chaos.

What's worse, the descendants of the Old Maou, namely two certain Shalba Beelzebub and Katerea Leviathan, had 'dropped by' where Rias was living, and the Gremory heiress just so happen to be alone with Riser Phenex at the moment. The two perpetrators' objective was simple: they wanted to provoke the current Maous into action by killing off their siblings and close relatives. Rias, being the younger sister of Sirzechs Lucifer, was obviously their primary target.

Right now, before Rias' very eyes, the so-called husband of her whom she disgusted the most was being blown away again and again. Riser might be a capable Devil, but he can't hold his strength against both pure-blooded descendants of the ancient Maou, who were formidable foes in their own rights. Despite his innate regeneration ability, Riser Phenex seemed to have both his will and his life force drained with each blast.

It's not like Riser had stepped up to defend Rias from Shalba and Katerea. The man was too selfish and prideful to do that. He was merely in their way, and the two also decided that he needed to be got rid of for being another pure-blooded Devil who was contented with the present system. Rias herself wasn't having an easy time either, having to fend off the continuous attacks from Shalba's subordinates.

Oddly enough, she was somehow pleased at the sight of Riser being overwhelmed and toyed with. Moreover, Rias didn't even feel a pang of guilt for having such thought. If anything, she wished him would just die already.

Her wish came true about some moments later when Riser finally fell down on his knees and slowly faded into diminishing burst of flame.

Needless to say, it was her turn next.

Rias would be deceiving herself if she said that she didn't have fear in mind. Anyone would definitely do when they are alone, surrounded by stronger enemies and after having witnessed the decease of someone else. Plus, with everything in disarray, she doubted that help would be coming soon.

For unknown reasons, Rias had already accepted her fate of dying here. It's like she had expected this outcome ever since her marriage with Riser Phenex.

But that didn't mean she would go down without a fight. Rias was, after all, the heiress of the proud Gremory House. She would rather die in valiance like a true noble Devil than surrendering to her soon-be slayers.

With the «Power of Destruction» in both hands, she readied herself for the inevitable demise.

However, there was one thing that kept irking her 'til the end.

Even when facing death, Rias Gremory still felt hollow.

**...**

Eyes fluttered open.

Mouth gasped for breath.

Sweats poured on the porcelain skin.

And hands caressed her face with such tender that it calmed her down almost immediately, completed with voice muttering words of intimate consolation.

She glanced at the brown-haired boy beside her, and here he was, Hyoudou Issei, comforting her with all he could. The red-haired girl hugged him upon the sight of his face, which startled the boy for a bit. He didn't how to react than embracing her gently in turn while stroking her naked back.

It was another usual night for them, with both laying bare to each other in the truest sense of words.

However, Rias didn't know what triggered the nightmare – or was it really a nightmare? – after having spent hours on their nightly ritual (the indication of which I shall leave to your imagination). Perhaps it was due to her mother talking about having another grandchild, the pressure from all other girls who got their eyes on her adorable lover, or the stress of recent battles was simply getting to her.

But the lingering sensation from her nightmare was so tangible that she had doubts about whether it was truly a dream, or what she was feeling right now is a dream itself. She could hardly reject the possibility that the moment she was having now might be some sort of a fantasy she dreamed of in the afterlife.

All uncertainty was washed away though as the only man who could warm up her heart reassured her with words she wanted to hear the most.

Words that promised her the whole world with him at her side.

Like a spell chant, it eased her mind instantly and made her realize once again that Ise was undeniably her destined one, that she would love nobody else than him.

Then she remembered a line she had heard somewhere, when an anonymous person once said.

"_Does it really matter in the end whether you are dreaming of being a butterfly,  
or a butterfly dreaming of being you?"_

Rias Gremory didn't know what others' answers were, but honestly, to her, it doesn't matter; because the only reality she believed in is the one with Hyoudou Issei as her soul mate. Even if she is dreaming of him being by her side, then she would rather never wake up.

At least with him, she wouldn't have to feel hollow anymore.

* * *

**A/N:** Been away from fanfiction for God knows how long. Too busy with everything since I started working abroad. Just being back into the hang of writing with this one. I don't know if I really get the gist of it yet. Tell me if it's awful. I will try to improve my writings, if I have time to write another or continue my other long fic, that is.


	2. Hollow x2

**...**

_**HOLLOW x2**_

**...**

Hyoudou Issei honestly have no idea how his life has turned 180 degree just like this.

He didn't remember having a brilliant mind as a genius, nor an outstanding courage as a superhero. And yet Fate had chosen him as the successor of Boosted Gear, a weapon that was said to be able to kill God if fully mastered.

It all started with a false date.

Being an unpopular and non-remarkable person for most of his life, Ise was somehow confessed by a young beauty. Needless to say, he was thrilled beyond comprehension and made the best plan he could come up with for their first date.

Everything was going smoothly according to his fantasy, until at the end of their date, that girlfriend of Ise asked him to die for her.

After that, it all happened so fast in a blur, and before he could regain himself, a red gauntlet had already replaced his current left arm, along with the bloody body of a Fallen Angel that was his so called girlfriend moments ago.

Yeah, he had just murdered someone. Although that person was trying to kill him first, it didn't change the fact that he had taken life of another living being away.

It scared him, it _terrified_ him.

Even in his wildest dream, Ise couldn't fathom the very thought of killing someone, much less than actually doing it. Add to the fact that he had discovered an unnatural power and a world he had no knowledge of until now.

Worst of all, his ordeal didn't stop there.

For whatever reason it was, the force that his supposed 'girlfriend' belonged to had begun chasing him down. Ise had to abandon everything he had once held and everyone he had known of to escape, including his own parents.

It took years and years for him to train himself as well as eluding his pursuers in every single step, going wherever his legs brought him to.

Physically strained, emotionally drained, he couldn't place his trust in anyone else but himself and continued to run senselessly, not knowing whether a tomorrow will ever come for him at all.

Along the way, a hole started to appear inside his soul, and it eventually became hollow.

**...**

On one peaceful day – a day that he deemed safe enough to relax – while Ise was pondering the meaning of the gauntlet in his left arm and the dragon dwelling inside it, one particular man approached him.

He introduced himself as Cao Cao, the descendant of the famous ruler with the same name of Wei dynasty in the ancient history of China.

Ise's first impression of the man was that he is an intellect and cunning person, which was obvious from the way he talked as well as which manner he carried himself.

He told Ise what exactly is the kind of this world they are living in, from which he only had some glimpse of from his occasional communication with Ddraig, and that he also wielded another top-ranked Sacred Gear, the True Longinus.

But most of all, he had come to the boy to offer him an invitation to join his group, the Heroes of Gaia, to fight for humanity against all kinds of non-human beings together with many other people who are either descendants of legendary heroes or wielders of Sacred Gears just like them.

Truth to be told, for the first time since the abandonment of his previous life, Ise was genuinely excited.

Excited that he had found a way to escape this meaningless manhunt from an unknown force which he previously had no power to resist. Excited that he could become an ally of justices for human just like those movies and stories he loved when he was still a child. And excited that he might have finally attained an answer to the meaning of his own existence, a question that he been constantly asking himself.

Needless to say, the boy had agreed to join in a heartbeat.

From that point on, a seemingly path of hope had stretched out before him. He underwent all kinds of brutal trainings, all forms of mental hardships, and all sorts of deadly clashes with forces from various realms. Despite how every single one of the enemies Ise encountered mocked him that he was the weakest host of the Boosted Gear's history, he usually betrayed their expectations of him and proved them just what amazing achievement a human can pull off given enough will.

And with each battle he came through, the brown-haired boy simply fortified his strength further and hardened his will tougher.

It was a path of glory for him.

Still, no matter how glorious he get, there was always an emptiness lying inside his heart. He might keep telling himself that it was nothing, but deep down, he knew better than anyone else about the truth.

After all, how can you hide hollowness when it's literally there to greet you every time you confronted yourself?

**...**

Inevitably, just like every Boosted Gear host before him, Ise come face to face with his nemesis, the current bearer of Divine Dividing, Vali Lucifer.

To say that he was strong was a big understatement. The man was atrociously powerful, far apart from any opponent that the brown-haired boy had fought with, and it didn't help much that he also carried the blood of the original Lucifer, one of the mightiest Devils ever known to walk both Heaven and Underworld, thus making him the strongest Hakuryukou.

Human against Half-Devil, Red turned Crimson against White turned Silver, and one who fought for protection against one who fought to seek strength.

Their battle was bloody and devastating.

Despite having fought valiantly, in the end, Ise was still overwhelmed by Vali. As such, the battle almost concluded with the latter's triumph.

But during the last moments, Ise was consumed by Ddraig's wrath due to his near-death state and tap into his own life force, summoning the ultimate form of his Sacred Gear, the «Crimson Welsh Juggernaut Drive» mode.

The battle raged on again, and after what seemed like an endless show of carnage and destruction, Ise came out victorious, slaying Vali in the process.

However, every power comes with a price, and the boy had to pay his short-lived victory with his own soul.

Somewhere inside him, though, he thought that this might be the best outcome. The boy who had once lived a carefree and normal life started to gradually lose his purpose with each battle he threw himself into, deluded by his own strength, until he became nothing more than a soulless husk. Death on a battlefield was how he envisaged his end, and since his vision came true, he believed that he had finally earned a peaceful finale to his life full of violence.

If only he had known what a hollow peace it was.

**...**

Even though every life normally ended with death, to Ise, however, Fate seemed to have disagreed on that, in a way that was both kind and cruel.

Cao Cao was a sly man, by all accounts, and he would not let one of his greatest pawns to die so easily. So he used the Holy Grail, which he had just stolen beforehand, to revive Ise completely with both his Boosted Gear and Vali's Divine Dividing in a body made of dragon flesh, a feat that had never been possible until now, hoping that he would be able to create and command the most powerful being that could rival even Great Red and Ophis.

But he couldn't foresee that he was attacked immediately when Ise emerged from the Well of Souls and caught him off guard.

The brown-haired boy was not his usual self anymore. Having dwelled inside the consciousness of so many fallen beings, he gained a massive amount of knowledge, and the wisdom to understand that his former comrade's intentions were not what he claimed to be, that his actions would eventually lead to mankind's downfall. Thus, Ise had decided that he would have to end Cao Cao's life himself.

At first, Cao Cao was overpowered by the newly resurrected Ise as he had both Dragon Emperors at their fullest strength, given the kind of body he had, which later forced the man to use the forbidden form of True Longinus, «Truth Edea».

Ironically enough, True Longinus had a will of its own, and during the moments of activating «Truth Edea», it had chosen Ise's ideal instead of its original master.

It went without saying that the Chinese man met his demise, but not before he left his last words of advice for the boy.

"_The powers you wield shall be the end of yourself."_

Acknowledging the man's words respectfully, Ise took over True Longinus and Holy Grail, embarked on another conquest to protect humanity all by himself, believing that no one else beside him could shoulder the burden.

At this point, the hollowness had enveloped his whole soul, and the once naïve boy was only a shell of his former self, fighting a battle he had no hope of ending, all but forgotten the desire to seek an answer to his previously mortal existence.

**...**

His dream stopped abruptly, and he wake up in the middle of the night.

It got him some time to steady his breath and calm down as he sat on the bed contemplatively.

The dream had obviously shaken him more than he had thought. Ise wondered if that was how his life would have played out had he not become a Devil, a life full of violence and hopeless future, not to mention the constant hollow feelings that kept weighting on his soul in every step he took. The brown-haired boy couldn't help but asked himself.

"_What is it that had been missing from my other life?"_

He, surprisingly, soon found the answer to that as he felt the slight tremble on his side and glanced at _her_.

There she was, Rias Gremory, in nothing but her birthday suit, breathing heavily and eyes twitching as she mumbled incoherent things to no one in particular.

It seemed that she was also having a dream, or to be more precise, a nightmare. Sweats began pouring on her porcelain skin, and as if she knew that he was awake, Rias immediately opened her eyes and stared at the ceiling with a horrified expression.

It didn't even take Ise a mere second to swoop down at her, caressing her face and muttering words of comfort that he would give no one else but her. She hugged him upon hearing those words, which startled him a bit as he had never seen her this vulnerable before, but he regained his composure quickly and embraced her gently, hoping that her nightmare would wither away from her mind.

All the while, he understood something as he stroked her back.

Rias Gremory was undeniably the soul mate of his heart, and he would gladly sacrifice everything in order to stay by her side and make her happy, even if it means trading the whole world. With the girl still being terrified inside his arms, the brown-haired boy did exactly what he had thought.

He promised the world with him at her side.

Unbeknownst to both of them, their hollowness had vanished without a trace, leaving behind a couple determined to spend their lives together forever.

And that, was how they achieved their own happily ever after.

* * *

**A/N:** This is a parallel chapter to the first one. I write it down since it seems inappropriate to let only one of our favorite couple suffer alone, and I want to make it feel like they were born for each other. Anyway, I do hope that you enjoy this one as much as the first chapter.


	3. Hollow's End

**...**

_**HOLLOW'S END**_

**...**

Just as threats of death looming in on Rias Gremory, a torrent of massive unfamiliar memories rushed into her mind.

Memories of a different life where she met and revived a certain brown-haired boy to be one of her servants, who later wormed his way into everyone's heart with his unlikely kindness, his unwavering courage and his unshakable will. Most important of all, it was him who saved her from her blighted fate, who softened her heart, and the one who made her fell in love with.

Those memories were so vivid, so genuine, so heartfelt, and so _damn_ pleasant that she had unconsciously shed her tears down onto the floor. She cried because that life full of vigor and passion could have been the life she led, but instead, she was bound to this cursed destiny, unable to escape from her loveless marriage and the impending demise.

More than that, it took her great effort not to drop on her knees right then and there and wept as if mourning for the loss of a person dearest to her.

Then she heard their sadistic snickers and scornful mockeries, those that were about to take her life for their arrogant pride and selfish belief.

They thought she was shedding tears due to fear of her own death. They thought that she was nothing more than a self-conceited girl who only knew how to live an extravagant and luxurious lifestyle. And they thought that she deserved to get whatever punishment they shall deliver to her.

But how could they understand when they know naught of her struggle, of her solitude, and of her hollowness?

All of a sudden, fear and sorrow disappeared completely from Rias' mind, replaced by a newfound rage and a fierce will to live.

No, she would not let these people ravage her however they wanted, she would not accept her fate of dying here. She still had to search for that brown-haired boy and tell him how much he meant to her in this world. She shall survive, she _must_ do, no matter what the cost is.

The Devils that confronted Rias was taken aback momentarily because of her unexpected resolve, but they gained their composure back and began to attack.

Oh, she would make them pay for underestimating her.

**...**

After pummeling another giant beast made from «Annihilation Maker» to the ground and finishing it off, Ise took a look at the scenery before him.

The Underworld was in its most wretched state ever since the Great War due to the Old Maou Faction's coup d'état. The sky was darker than its usual color, ruins dominated the whole area as far as the eyes could see, and demonic flames wreaked havoc at everything in their path, burning both the living and the death together.

The reason that Ise being here was to clean up whatever the mess those remnants of Old Devils had caused.

He wouldn't even bother to do it if that had nothing to do with him nor humanity in the beginning. After all, this is the Devils' internal conflict and their own realm, and he simply had no obligation to help either side of them.

However, the circumstances this time was a bit different.

Because he possessed both «True Longinus» and «Holy Grail» at the same time, Ise inevitably became the target of the Old Maou faction since they were the one holding the latter Sacred Gear that was stolen by Cao Cao.

What the old Devils didn't expect was how powerful the brown-haired boy had become.

Regardless of how many assassins they had sent after him, Ise would always slay each and every single one of them with such ease that it frightened them. Then in moments of desperation, they decided to stop chasing him down and instead focus on the coup d'état that they had been planning for a long time.

When he heard about what was happening in the Underworld, Ise had first chosen to stay silent and not to act on it.

But there were various reasons telling him to do otherwise. He knew that the current Devils of this generation mostly didn't have any ill intentions towards mankind, combining with the fact that if the Old Maou indeed succeeded, Earth would be their next target.

Or at least that were what he was trying to persuade himself.

Suddenly, a strange sense of sentiment washed over him, together with memories of another life that he had no knowledge of.

Memories where he had met and become a certain Devil's servant, memories where he could still living his days normally as a student despite the frequent battles he engaged in, and memories where everybody around him became the comrades that he could trust his life with, even including his once enemies.

Relief and Anger, Gratification and Envy, Contentment and Resentment, many opposite emotions were swirling inside his mind. Oh how he desired that life so, how he craved for that life so, yet still couldn't do anything but to be glad that somewhere in the other timeline and dimension, another Ise was having a happy life.

Then he abruptly flew off into distance, going straight to a place that he didn't even expect to exist in his mind. Something compelled him to go forward, and for once, he listened to it without questioning or understanding why. He simply knew that if he was to be late, then terrible things would happen that shall make him regret for the rest of his life.

And he had already regretted a lot of things, so he could do nothing but feverishly hope that he would make it in time.

**...**

She stumbled back and fell down on her knees, body battered and bruised from the merciless assault of her enemies.

Rias had given more of a resistance than she had thought she could, which made her assailants be slightly surprised because of the determination in her attacks. But they finally pushed her to her limit, and she was barely able to use her last strength to stay awake amidst the heavy urge to close her eyes due to weariness and blood dripping from above her eyes.

In frustration, helplessness and bitterness, she thought.

"_So is this the end for me?"_

And just as all hopes were lost for her, something suddenly crashed from the sky.

The impact was so great that it shook the whole area and made the entire mansion collapse, killing some Devils in its way. Shalba and Katerea were luckier as they came out unscathed, but the aura emitting from the perpetrator was alarming. They immediately put on their guard as instincts told them that this was no ordinary being.

After the smoke caused by the crash had settled down, appeared a figure clad in an enormous armor with a mixture of Crimson and Silver colors, complete with three pairs of gigantic Dragon Wings of light.

Before they could even register what was going on, it was over in an instance.

The Dragon knight was so unbelievably fast, so ridiculously strong, and so overwhelmingly powerful that all the hostile Devils in the vicinity were killed within mere seconds. Despite being descendants of Maous, Shalba and Katerea couldn't escape from their deaths as they quickly fell one after another.

When all is said and done, the Dragon knight turned to Rias' direction.

Although this was the first time they have truly met each other, she felt that she had known him for a very long time. And when he released his armor, her doubts were confirmed.

Here he was, Hyoudou Issei, the one she had been constantly searching for, the one she had dreamed of being with, and the one who shall fill up her hollow heart.

He strode slowly toward her, and she stayed unmoving where she was. Both of them were taking their time as if they were still ascertaining the other's presence.

When he finally stood in front of her, Rias delicately reached her hand and touched his face, trying to make sure that he was not an illusion she created in her mind.

And after what seemed like an eternal moment of silence and serenity, all restrains were broken loose as she embraced him tightly, afraid that he would vanish if she ever let go of him, wailing out every emotion she had bottled up inside her fragile body. Ise also embraced her in return while trying his best not to further hurt her already injured state, being thankful that he arrived in time and got rid of those who threatened her life.

Two hollow hearts at last had found each other and began a new journey to a brighter future for them.

**...**

Just as he was embracing and comforting his lover, somehow Ise felt that he wouldn't have to worry about what could have happened to his other self from another lifetime and dimension. He wasn't sure of the cause, but his intuition told him that the other Ise have already found his own happiness despite the constant encounters of violence and death.

Little did he know that the beautiful red-haired girl in his arms was also feeling the same thing.

Rias' dream had stopped right before she could witness her other self's death. It was greatly depressing to see a girl who had never experienced true love to die without even finding out who was her soul mate, and Rias shuddered at the mere thought that she could have been suffering the same fate if not for the boy embracing her.

It was odd, considering that she didn't know whether her nightmare actually occurred or not. But something told her otherwise, that it was real, and that her parallel self was finally able to meet the one that had been missing from her life.

Both of them then closed their eyes in blissfulness, silently whispering their gratitude to Fate.

" "_Thank you for letting me meet him/her, and thank you for letting us stay together..." "_

Souls from different lives connected, and happiness was achieved twice.

**...**

_**The End**_

**...**

* * *

**A/N:** I know that somebody might be saying something like this: "Is this guy for real? He marked this as complete and yet kept adding new chapters to it!"

I swear, this wasn't in my intention. Despite wanting to finish it totally, I always feel like writing more and more to it every time I read back on it. And guess what, my hands moved before I could comprehend what I was doing :D

Anyway, this is the actual final chapter. I hope that you all have enjoyed this fic so far as much as I wrote it.

See you guys in my next story, probably.


End file.
